Endoscopes are optical instruments that permit a user to see around or through an obstruction, to see something that would otherwise be concealed. For example, endoscopes are used to permit doctors to see inside a patient's body without major surgery; some endoscopes require a small access incision to be made in the patients body. Endoscopy systems typically comprise an illumination light source, illumination light guides to conduct the illuminating light to the tissue under observation, imaging optics, and image collection light guides to conduct the image of the tissue to the observer. The image can be detected by the human eye or by an imaging device such as a CCD camera. An imaging device usually employs an image display system such as a CRT monitor to relay the image to the human eye. In some cases, the image detected by the imaging device or camera may be digitized, stored in memory or on media, processed with various software algorithms, and/or then converted to an analog video signal that can be displayed on the image monitor.
Physicians and surgeons use endoscopy devices to examine tissue and decide on treatment. Having a sound basis to compare normal and abnormal tissues is essential. If changes occur in the way the system presents the visual information, the physician's or surgeon's ability to interpret results is compromised. To assist accurate diagnosis and treatment, hospitals and clinics must have ways to measure and quantify the performance characteristics of endoscopy devices and of the systems comprising such devices.
Components of endoscopes, and endoscopy systems, can become degraded, or can be incorrectly adjusted, or can fail to operate or otherwise fail to perform. It can be difficult to determine if an endoscope is not performing adequately, particularly where the problem comprises inaccurate color representation. Problems arise from a variety of sources, including difficulties with intensity or spectral characteristics of the illumination lamp or light transmission elements, and bad image sensors, software programs or display systems. Other systems can also fail, such as air, water and suction lines.
Endoscopes typically have problems in one of three areas. First is image quality, which can be defined as the accuracy with which the image viewed by the operator represents the target under observation. In other words, does a straight line stay a straight line when viewed through the endoscope? Second is the photometric quality of an image, which can be defined as the spectral distribution of the light emitted from the target. Third, is the physical integrity of the equipment, particularly the endoscope itself, which can sustain optical damage, leaks or blockages in air and fluid lines and damage to the mechanical control components or envelope.
A variety of approaches have been pursued to remedy these problems. See, e.g., U.S. Pat. No. 5,820,547; U.S. Pat. No. 5,841,525; “The Endo Tester™—A Lab VIEW-Based Automated Test System for Fiber-Optic Endoscopes” by Eric Rosow, Hartford Hospital, and Joseph Adam, Premise Development Corporation (brochure); PCT WO 97/07627 (EP0845187 A 19980603); U.S. Pat. No. 5,369,481; U.S. Pat. No. 5,738,824; WO 98/58682); U.S. Pat. No. 5,494,530.
However, there has gone unmet a need for improved apparatus and methods for assessing the color, image or structural characteristics of an endoscope. The present invention provides these and other advantages.